OnlineWoerterBuecher.de - Lexikon, Free On-line Dictionary of Computing



	OnlineWoerterBuecher.de

Navigation

Start

Deutsch-Englisch

Deutsch-Spanisch

Enzyklopädie

Internes

Impressum

Kontakt

Lexikon

functional database

e, language> A ef="module.php?name=Lexikon&file=search&eid=1&query=database">database which uses a {functional language} as its {query language}. Databases would seem to be an inappropriate application for functional languages since, a ef="module.php?name=Lexikon&file=search&eid=1&query=purely functional language">purely functional language would have to return a new copy of the entire database every time (part of) it was updated. To be practically ef="module.php?name=Lexikon&file=search&eid=1&query=scalable">scalable, the update mechanism must clearly be ef="module.php?name=Lexikon&file=search&eid=1&query=destructive">destructive rather than functional however it is quite feasible for the {query language} to be purely functional so long as the database is considered as an argument. One approach to the update problem would use a ef="module.php?name=Lexikon&file=search&eid=1&query=monad">monad to encapsulate database access and ensure it was {single threaded}. Alternative approaches have been suggested by Trinder, who suggests non-destructive updating with shared data structures, and Sutton who uses a variant of a Phil Wadler' s ef="module.php?name=Lexikon&file=search&eid=1&query=linear type">linear type system. There are two main classes of functional database languages. The first is based upon ef="module.php?name=Lexikon&file=search&eid=1&query=Backus">Backus' ef="module.php?name=Lexikon&file=search&eid=1&query=FP">FP language, of which ef="module.php?name=Lexikon&file=search&eid=1&query=FQL">FQL is probably the best known example. ef="module.php?name=Lexikon&file=search&eid=1&query=Adaplan">Adaplan is a more recent language which falls into this category. More recently, people have been working on languages which are syntactically very similar to modern {functional programming language}s, but which also provide all of the features of a database language, e.g. bulk data structures which can be incrementally updated, type systems which can be incrementally updated, and all data persisting in a database. examples are ef="module.php?name=Lexikon&file=search&eid=1&query=PFL">PFL [Poulovassilis&Small, VLDB-91], and ef="module.php?name=Lexikon&file=search&eid=1&query=Machiavelli">Machiavelli [Ohori et al, ACM SIGMOD Conference, 1998]. ef="module.php?name=Lexikon&file=search&eid=1&query=Query optimisation">Query optimisation is very important for database languages in general and the ef="module.php?name=Lexikon&file=search&eid=1&query=referential transparency">referential transparency of functional languages allows optimisations which would be harder to verify in presence of ef="module.php?name=Lexikon&file=search&eid=1&query=side-effect">side-effects. [Trinder, P., "Referentially transparent database languages", 1989 Glasgow Workshop on Functional programming] [Breazu-Tannen et al., DBPL-91]. [Poulovassilis, VLDB-94]. (1995-05-09)

[ Go Back ]

Free On-line Dictionary of Computing

	All logos and trademarks in this site are property of their respective owner. Page Generation in 0.1081 Seconds, with 16 Database-Queries